cgroup-rstat-flushing: New contended counter per level

# HELP ebpf_exporter_cgroup_rstat_lock_contended Lock contention counters per cgroup level # TYPE ebpf_exporter_cgroup_rstat_lock_contended counter ebpf_exporter_cgroup_rstat_lock_contended{level="0"} 36 ebpf_exporter_cgroup_rstat_lock_contended{level="1"} 847 ebpf_exporter_cgroup_rstat_lock_contended{level="2"} 415 ebpf_exporter_cgroup_rstat_lock_contended{level="3"} 0 ebpf_exporter_cgroup_rstat_lock_contended{level="4"} 0 ebpf_exporter_cgroup_rstat_lock_contended{level="5"} 0 Signed-off-by: Jesper Dangaard Brouer <[email protected]>
cloudflare · Aug 1, 2024 · 72b7a2f · 72b7a2f
1 parent 727a241
commit 72b7a2f
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diff --git a/examples/cgroup-rstat-flushing.bpf.c b/examples/cgroup-rstat-flushing.bpf.c
@@ -45,6 +45,13 @@ struct {
 	__type(value, u64);
 } cgroup_rstat_locked_yield SEC(".maps");
 
+/* Per cgroup level lock contended counter */
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__uint(max_entries, MAX_CGRP_LEVELS + 1);
+	__type(key, u32);
+	__type(value, u64);
+} cgroup_rstat_lock_contended SEC(".maps");
 
 /** Measurement#1: lock rates
  *  =========================
@@ -76,6 +83,20 @@ int BPF_PROG(rstat_locked, struct cgroup *cgrp, int cpu, bool contended)
 		(*cnt)++;
 	}
 
+	/* What cgrp level is interesting, but I didn't manage to encode it in
+	 * above counters.  As contended case is the most interesting, have
+	 * level counter for contended.
+	 */
+	if (contended) {
+		u32 level = cgrp->level;
+
+		if (level > MAX_CGRP_LEVELS)
+			level = MAX_CGRP_LEVELS;
+
+		read_array_ptr(&cgroup_rstat_lock_contended, &level, cnt);
+		(*cnt)++;
+	}
+
 	return 0;
 }
 

diff --git a/examples/cgroup-rstat-flushing.yaml b/examples/cgroup-rstat-flushing.yaml
@@ -21,4 +21,11 @@ metrics:
           size: 4
           decoders: # contended boolean converted to 0 and 1
             - name: uint
+    - name: cgroup_rstat_lock_contended
+      help: Lock contention counters per cgroup level
+      labels:
+        - name: level
+          size: 4
+          decoders:
+            - name: uint